On Wed, 22 Dec 2004, Dave Arquati wrote:

Tom Anderson wrote:
On Tue, 21 Dec 2004, Dave Arquati wrote:

Tom Anderson wrote:

On Sun, 19 Dec 2004, John Rowland wrote:

"Tom Anderson" wrote in message
...

On Sat, 18 Dec 2004, Dave Arquati wrote:

I believe even in the tunnel to Bank for an underground station to
replace Tower Gateway, which was originally going to be closed in
favour of Bank, but DLR decided operationally that it was too
useful to close.

Do you have any (pointers to) more information on this?

The flat straight spot between two very steep curved sections is
quite obvious if you ride the DLR to or from Bank, especially if you
sit in the front.

Is that right after the junction with the Tower Gateway branch,
immediately south of Tower Gateway station? That's the only
likely-looking straight bit i can see on the (admittedly quite poor)
maps i can find. Although it is on the right tunnel, sadly, it's even
further from Fenchurch Street than Tower Gateway - although perhaps
closer to Tower Hill.

Many c2c trains now stop at either Limehouse or West Ham to provide
access to Docklands more rapidly than going into Fenchurch St and out
again.

Still, all things being equal (which they aren't) it would be preferable
to have better interchange, surely?

Yes, of course - but given the costs of changing the existing provision
(the flat, straight section of tunnel and existing Docklands area access
from Limehouse and West Ham) it wouldn't really stand up in a
cost-benefit analysis.

No, of course not. But i'm always hopeful!

In any case, DLR are unlikely to close Tower Gateway station at its
current location; it's extremely useful.

Why?

When there are operational problems at Bank (for example fire alerts,
Tube strikes, that sort of thing), trains can still get to/from the
City. That wouldn't necessarily be possible with an underground station
in the safeguarded location, as trains would have to reverse in the
sidings beyond Bank.

Could there not be a (and correct me if this is not what i mean) trailing
crossover? Like so:

----+----------
to Bank \ ### to Thatcherite nightmare wasteland
------+--------
Tower Moat
Station
or whatever they call it

So a train from the east could pull in to Tower X on the southern track,
then run on west, over the crossover, then reverse and pull into the
westbound platform.

I suppose the tunnels have already been built, and retrofitting this would
be hugely expensive.

Incidentally, and on a bit of a tangent, this arrangement would also work:

------+--------
/ ###
----+----------

With trains doing the actual reverse on the westbound track - you might
call this a right-rail reverse, and the other a wrong-rail reverse. Which
one is actually used in practice? Why?

It also provides additional reversing capacity in the City for Beckton
trains,

A few lines from here, you say reversing capacity isn't an issue!

and could be used to turn trains short if there is some operational
problem on the Isle of Dogs (although I don't know if that ever
happens!).

Not sure i get that. Where are these short-turned trains coming from and
going to? I can't see how Tower Gateway is any better than Bank / Tower
Moat for this.

However, it is due to be reduced to a single but lengthened platform as
part of the capacity improvement project, as the island platform would
become dangerously overcrowded.

When you say 'single', do you mean it will still be an island, or will it
become a single-face platform? I can't see the latter being great for
capacity, but if reverses aren't a limiting factor, i suppose it would
work.

I mean a single-faced platform (sorry, I didn't make that clear). This
is only really a capacity reduction of 25%, as 2 two-car platforms will
become one three-car platform. The problem is that the island platform
cannot be lengthened to accommodate additional passengers without being
widened - and there is no room to widen the viaduct. Reversals aren't a
huge issue on the DLR thanks to the computer control; the limiting
factor is how quickly you can disembark a trainload and embark the next
trainload, and that is partly limited by platform space.

Two faces still gives you more capacity, since you can be handling two
trains at once (sort of - trains can interfere with each other through the
crossover, which makes things slightly complicated).

There was once a plan to extend Tower Gateway over Minories into the
university building opposite, bringing it closer to Fenchurch Street,
but I don't know what happened to that idea.

Hey, maybe the real solution is to move Fenchurch Street Station down the
line a bit ...

tom

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